This invention relates to an improved microscope optical relay system and back aperture viewer. More particularly, this invention relates to a relay system including two identical optical components having different front and back focal lengths with one component axially arranged opposite the other. This invention also is directed further to a back aperture viewer for observing optical elements located in a station at a location optically equivalent to the back focal plane of a microscope objective.
A number of microscopy techniques require positioning an optical element either at or very near the back focal plane of a microscrope objective. Difficulties are encountered in many objectives, particularly those of higher power, because the back focal plane is located within the physical structure of the objective. Often, the back focal plane is located within a glass lens element. U.S. Pat. No. 3,628,848 issued to Georges Nomarski on Dec. 21, 1971 describes certain microscopy techniques in which it is desirable to locate an optical element in the back focal plane of the microscope objective. Nomarski also notes that, because of the inaccessability of the back focal plane, it may be desirable to use a relay providing a remote station in which such optical elements can be located in a position optically equivalent to the back focal plane of the objective. Optical elements of the type desirable to locate in such a station are described in commonly owned co-pending application Ser. No. 594,989, filed July 11, 1975.
It is an object of the present invention to provide an optical relay for obtaining a remote station optically equivalent to the back focal plane of a microscrope objective.
It is a further object of the present invention to provide such a relay without introducing significant aberrations of the of the object image.
It is a still further object of the present invention to provide a viewer for selectively observing the positioning of an optical element at such a remote station.